I find it interesting that Slingshot does not offer any method to adjust the angle of attack of the stabilizer. Most other brands offer shims or washers to adjust. I still consider myself a newbie (maybe 35 sessions on my Dialer 145 then 2018 Wizard 125), but I'm considering playing around with the angle. When I started out with the Dialer I was surprised how easily it breached with the fuselage in the B position. As I gained more experience and bought an i76 wing I didn't breach as much. Then onto the Wizard things improved a bit more. When I sold my Dialer to a friend who used his own SS foil, he didn't have as much of a breach issue starting out. It made me wonder if there is much variation in the stabilzer angles between foils. It seems like a little variation in machining could make a big difference in the angle.
I saw a video of a foil pro racer using an angle measuring tool so I got one and measured my own stabilizer. See photos. You will note I measured an angle of -3.7 degrees. Note also this is measured against the fuselage (as the pro did), not the attack angle of the front wing. What do you think of -3.7? From what I read here and other places it seems quite large, producing down force and therefore more upthrust from the entire foil (and more front foot pressure/potential breaching force). If I use a washer under the the leading edge of the stab to reduce the angle to maybe -2, I wonder how the foil with react. Will I get less lift, more speed, less front foot needed? Anyone here measured their own angles?
Thanks for ideas.
I don't have a tool to measure the angle, but I did shim my rear stab for less lift by adding a 0.5mm shim under the front screw and 0.25mm shim under the back. According to my trigonometry, this gives me about -0.5deg of AoA.
The effect is slightly less than if I was to move the fuse to A position, but noticeable.
The main reason I shimmed it, is so I don't have to assemble/disassemble in the A position, which is more effort (need two hex sizes).
I used slot shims, trimmed to size.
Since you use a matching foil and board, I dont think you need to shim. Less front foot pressure than what is recommended by the manufacturer is in my opinion pretty much always a bad thing for freeriding. (as opposed to more front foot pressure) For F-One we have also opted to not offer any adjustment, other than making something yourself. Keeps things simple.
You could probably make your foil a little faster while maintaining the same balance if you wanted to, by using some switch fuse magic and decreasing the stab angle.
Hi Marc,
I only have an analog incidence meter from building model airplanes. When I measured my Slingshot, it was slightly below -4degree, so same. As you can trim the foil by switching the fuselage, it is not that big of a problem. And regarding the age of the construction, they are still on a good level.
i See a demand for tunability, because the whole system depends on so many variants. Different rider-weights, tuttle-box-positions and so on. Shims are a good way and easy to use, because they are reproducible. On my Horue foil it was always guess-work, but it was way off for my 95kg anyway.
Select to expand quoteWhiteofHeart said..
You could probably make your foil a little faster while maintaining the same balance if you wanted to, by using some switch fuse magic and decreasing the stab angle.
Please , could you explain that better and how would you make it?
Select to expand quotew100 said..WhiteofHeart said..
You could probably make your foil a little faster while maintaining the same balance if you wanted to, by using some switch fuse magic and decreasing the stab angle.
Please , could you explain that better and how would you make it?
Decrease angle on the stab with a shim (personally I find stacking a cut-up credit card under one of the screws until the desired angle works very well), then move the front wing forward to maintain balance.
Select to expand quotemarc5 said..
I find it interesting that Slingshot does not offer any method to adjust the angle of attack of the stabilizer. Most other brands offer shims or washers to adjust. I still consider myself a newbie (maybe 35 sessions on my Dialer 145 then 2018 Wizard 125), but I'm considering playing around with the angle. When I started out with the Dialer I was surprised how easily it breached with the fuselage in the B position. As I gained more experience and bought an i76 wing I didn't breach as much. Then onto the Wizard things improved a bit more. When I sold my Dialer to a friend who used his own SS foil, he didn't have as much of a breach issue starting out. It made me wonder if there is much variation in the stabilzer angles between foils. It seems like a little variation in machining could make a big difference in the angle.
I saw a video of a foil pro racer using an angle measuring tool so I got one and measured my own stabilizer. See photos. You will note I measured an angle of -3.7 degrees. Note also this is measured against the fuselage (as the pro did), not the attack angle of the front wing. What do you think of -3.7? From what I read here and other places it seems quite large, producing down force and therefore more upthrust from the entire foil (and more front foot pressure/potential breaching force). If I use a washer under the the leading edge of the stab to reduce the angle to maybe -2, I wonder how the foil with react. Will I get less lift, more speed, less front foot needed? Anyone here measured their own angles?
Thanks for ideas.
I have a large vernier that I have knotched for the leading and trailing edge of the wing and stabilizer. It fits both the I84 wing and the S48 stabilizer. When I measure the S48 stabilizer angle, it is in referenced to the I84 wing. I measure about -1 degree and about -2 degrees with the I76 wing / S42 stabilizer like you have. White of Heart talks about getting the n-th degree of performance from his setup by adjusting his stabilizer angle. But I don't know if that's the case with Slingshot. The I76/S42 wing which is probably 30 percent faster than the I84/S48, but it doesn't glide thru the lulls as well. Since we don't have a steady sea breeze where I sail, I've grown a preference for for the I84/S42 setup. If your setup is working, don't look a gift horse in the mouth.
When received my (not very cheap) full carbon AFS 95 foil I was so surprised that the stabilizer wing had no shims, nor any way to insert a washer or anything. AFS just designs their stabs without them.
Result: I could not have been happier.
All I was left with to adjust were footstraps (less frequent OR never), and mast track (more regular). After a few outings I found the perfect mast track position(s) for my foil, board and (two) sail(s). I marked the mast track on the board with color marker and that was it. Always happy with it. Only adjusting if high or low wind with mm's.
Afterwards never once on the water I thought... "ooh I need to adjust my shim", do I need more or less.
Nope: I just adjust with my body instead when I need to. And if I am adjusting too much I stop and move the mastrack a bit.
I think the whole shimming option just creates more 'unrest in the mind'.
I remember with the previous NP glide foil which had the washer for stabilizer wing, I was all the time adding / removing the washer.. never happy.. all the time doubting etc.
Moral of this post: keep it simple!
I have an AFS Wind95 and F800 wing, was working on getting up in light winds, 8-10 knots, and got 2 carbon shims from AFS, one for 15 and under, 2 for 10 and under, they really make a difference and I can get up now in 8-10 knots. Forgot to take them out after a light wind session, next session was 15-18 and board wanted to almost jump out of the water, did not know why until I decided to clean and lubricate the stab screws and found the two shims under the front screw! Now I always remove the shims after a session. The problem initially though was they made the tail of my Goya Bolt 135 sink more which caused drag, so I learned to move my front foot forward to level out the board to get it foiling and then carefully move my foot back into the front foot strap. On a deficated foil board this would not be an issue due to the wider high volume tail.
